Maturity and storage influence on the apple (Malus domestica) allergen Mal d 3, a nonspecific lipid transfer protein

Consumption of apples can provoke severe allergic reactions, in susceptible individuals, due to the presence of the allergen Mal d 3, a nonspecific lipid transfer protein, found largely in the fruit skin. Levels of Mal d 3 were determined in peel as a function of apple cultivar, position of the fruit growing on the tree, apple maturity, and postharvest storage by ELISA. As the apples mature, Mal d 3 levels increased, although the rate was dependent on cultivar and tree position. During storage, levels of Mal d 3 decreased in all cultivars (cvs. Cox, Jonagored, and Gala), the rate of overall decrease being greatest under controlled atmosphere conditions. There was no correlation between Mal d 3 levels and total apple peel protein, indicating specific alterations in Mal d 3 expression. Thus pre- and postharvest treatments (i.e., storage) can modify the allergen load in apple peel, the highest levels being found in overly mature and freshly harvested fruits.     

Influence of cultivar, harvest time, storage conditions, and peeling on the antioxidant capacity and phenolic and ascorbic acid contents of apples and pears

Apple and pear fruits are important sources of secondary plant metabolites and one of the major sources of dietary phenolics consumed all year round. The aim of this work was to identify the main variables influencing phenolic content and antioxidant capacity in apples. Higher phenolic and antioxidant contents were observed in some varieties (such as the Delbar Estival apple and Durondeau pear). Storage conditions were important. Our results also showed that fruits should be consumed rapidly after purchase and with their peel. After one week of domestic storage, the ascorbic acid content was found to decrease by 75%. Peeling led to a more than 25% decrease in total phenolics and ascorbic acid. The harvest time (at normal ripeness) had only a limited impact, but significant year-to-year variations were observed. In conclusion, well-chosen and well-stored apples and pears may contribute to an antioxidant-rich diet if consumed rapidly and with their peel.     

Detecting potential IgE-reactive sites on food proteins using a sequence and structure database, SDAP-food

The high incidence of food allergies, including oral allergy syndrome, represent major considerations when introducing new crops and foods. A new structural database of allergenic proteins, SDAP-Food, http://fermi.utmb.edu/SDAP/, has been developed to aid in predicting the IgE-binding potential of novel food proteins and cross-reactivities among known allergens. The site is designed to facilitate the first steps of a decision tree approach to determine the allergenicity of a given protein, based on the sequence and structural similarity to known allergens and their IgE binding sites. Immunological tests can then be used to confirm the predictions. A hierarchical procedure for identifying potential allergens, using a physical property-based sequence similarity index, has been designed to identify regions that resemble known IgE binding sites. As an example, SDAP tools were used to find food allergen sequences similar to an IgE binding site of the Jun a 3 allergen from mountain cedar pollen. The SDAP sequence similarity search matched the Jun a 3 epitope to regions in several food allergens, including cherry (Pru av 2), apple (Mal d 2) and pepper (Cap a 1), which are, like Jun a 3, members of the plant pathogenesis-related (PR-5) protein family. Homology modeling, using our EXDIS/DIAMOD/FANTOM program suite, indicated a similar surface location and structure for the potential epitope region on all of these allergens. The quantitative approach presented here can be used as part of a screening process for potential allergenicity of recombinant food products.     

Free galactose concentrations in fresh and stored apples (Malus domestica) and processed apple products

Gas chromatography was used to quantitate free galactose in Braeburn, Fuji, Red Delicious, and Spartan apples during cold storage, after thermal processing of apple slices and in juice produced using clarification and/or liquifaction enzymes. Spartan had significantly higher galactose levels as compared to Red Delicious apples, but changes in galactose in all varieties during 9 months of cold storage were insignificant. Blanching and canning decreased galactose levels, but doubling the thermal processing during canning increased the free galactose concentration detected in plant tissue. An enzymatic liquefaction aid used to prepare apple juice dramatically increased the free galactose content while a clarification aid caused only a slight increase due to its selective action on soluble pectin. These findings provide useful information for dietitians to base diet recommendations for galactosemic patients.     

Effects of phytic acid on peanut allergens and allergenic properties of extracts

Phytic acid would form soluble and insoluble complexes with proteins. Our objective was to determine if phytic acid forms insoluble complexes with major peanut allergens, and if such reaction results in a peanut extract with a lower level of soluble allergens and allergenic property. Extracts from raw and roasted peanuts were treated with and without phytic acid at various pH values and then analyzed by SDS-PAGE and a competitive inhibition ELISA (ciELISA). The ciELISA measured IgE binding using a pooled serum from peanut-allergic individuals. Results showed that phytic acid formed complexes with the major peanut allergens (Ara h 1 and Ara h 2), which were insoluble in acidic and neutral conditions. Succinylation of the allergens inhibited complex formation, indicating that lysine residues were involved. A 6-fold reduction in IgE binding or allergenic potency of the extract was observed after treatment with phytic acid. It was concluded that phytic acid formed insoluble complexes with the major peanut allergens, and resulted in a peanut extract with reduced allergenic potency. Application of phytic acid to a peanut butter slurry presented a similar result, indicating that phytic acid may find use in the development of hypoallergenic peanut-based products.     

丁香精油和丁香酚对苹果贮藏期病害及果实品质的影响

该文对丁香精油和丁香酚在离体和活体条件下对采后苹果的主要致腐菌苹果青霉、苹果灰霉、苹果炭疽、苹果轮纹、苹果褐腐和苹果腐心的抑制作用以及对贮藏期苹果品质的影响进行了研究。结果表明,在离体条件下,丁香精油和丁香酚对供试菌种有显著的抑制作用,最低抑制浓度(MIC)范围分别为0.15～0.30 mg/(100 mL)和0.15～0.35 mg/(100 mL),但不能完全抑制致腐菌在苹果果实上的生长。丁香精油和丁香酚能够抑制采后苹果腐烂率、呼吸强度和褐变指数的上升,以及可溶性固性物含量、可滴定酸和硬度的下降,延缓采后苹果的生理衰老,有利于保持苹果的品质和风味。加入CaCl₂后,抑菌效果和保鲜效果优于单一的丁香精油和丁香酚处理。作为一种可食性香料,丁香有望开发为纯天然的食品和果品保鲜剂。     

Influence of cultivar and processing on cherry (Prunus avium) allergenicity

Oral allergy syndrome is an immediate food allergic event that affects lips, mouth, and pharynx, is often triggered by fruits and vegetables, and may be associated with pollinosis. Here, we report on the allergenic pattern of different varieties of cherry (Prunus avium) and results obtained by applying several technological processes to the selected varieties. Whole cherries were submitted to chemical peeling, thermal treatment, and syruping processes, and the relative protein extracts were analyzed by in vitro (sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting analysis) and in vivo tests (skin prick test). Electrophoretic analyses demonstrated that there was no marked difference among cherry cultivars. Chemical peeling successfully removed Pru av 3, a lipid transfer protein (LTP) responsible for oral allergy syndrome in patients without pollinosis, leading to the industrial production of cherry hypoallergenic derivatives. Furthermore, the syruping process removed almost all allergenic proteins to whom patients with pollinosis are responsive. In vivo tests confirmed electrophoretic results.     

Antioxidant activity of apple peels

Consumption of fruits and vegetables has been shown to be effective in the prevention of chronic diseases. These benefits are often attributed to the high antioxidant content of some plant foods. Apples are commonly eaten and are large contributors of phenolic compounds in European and North American diets. The peels of apples, in particular, are high in phenolics. During applesauce and canned apple manufacture, the antioxidant-rich peels of apples are discarded. To determine if a useful source of antioxidants is being wasted, the phytochemical content, antioxidant activity, and antiproliferative activity of the peels of four varieties of apples (Rome Beauty, Idared, Cortland, and Golden Delicious) commonly used in applesauce production in New York state were investigated. The values of the peels were compared to those of the flesh and flesh + peel components of the apples. Within each variety, the total phenolic and flavonoid contents were highest in the peels, followed by the flesh + peel and the flesh. Idared and Rome Beauty apple peels had the highest total phenolic contents (588.9 +/- 83.2 and 500.2 +/- 13.7 mg of gallic acid equivalents/100 g of peels, respectively). Rome Beauty and Idared peels were also highest in flavonoids (306.1 +/- 6.7 and 303.2 +/- 41.5 mg of catechin equivalents/100 g of peels, respectively). Of the four varieties, Idared apple peels had the most anthocyanins, with 26.8 +/- 6.5 mg of cyanidin 3-glucoside equivalents/100 g of peels. The peels all had significantly higher total antioxidant activities than the flesh + peel and flesh of the apple varieties examined. Idared peels had the greatest antioxidant activity (312.2 +/- 9.8 micromol of vitamin C equivalents/g of peels). Apple peels were also shown to more effectively inhibit the growth of HepG(2) human liver cancer cells than the other apple components. Rome Beauty apple peels showed the most bioactivity, inhibiting cell proliferation by 50% at the low concentration of 12.4 +/- 0.4 mg of peels/mL. The high content of phenolic compounds, antioxidant activity, and antiproliferative activity of apple peels indicate that they may impart health benefits when consumed and should be regarded as a valuable source of antioxidants.     

苹果常温下组合动态气调贮藏技术的研究

动态气调是在气调基础上发展起来的一种新型贮藏保鲜技术,它可以抑制果实的衰老过程,延长贮藏时间。并减少贮藏腐烂损失。组合动态气调是一种更先进的技术。我们在常温下用合适浓度的CO₂和O₂在苹果入贮初期进行短期组合冲击,然后再选择能够满足苹果长期贮藏保鲜环境气体参数的塑料薄膜包装贮藏的组合动态气调技术,经1984、1985两年在苹果产区山东省平度县试验表明,对主要品种红星、金帅、青香蕉及国光具有满意的保鲜效果。     

Ester variability in apple varieties as determined by solid-phase microextraction and gas chromatography-mass spectrometry

Solid-phase microextraction (SPME) with a polydimethylsiloxane fiber coupled with gas chromatography-mass spectrometry (GC-MS) was applied to the study of variability in volatiles released by 13 apple varieties. The relative amounts of 40 esters and alpha-farnesene were determined. Principal component analyses of these results clustered the apples into three groups according to skin color: red, green, and red-green. Total ester contents were highest with the red cluster apples, and the green cluster apples had the highest alpha-farnesene levels. This technology was also applied to the monitoring of changes in volatiles for apples removed from controlled-atmosphere storage with subsequent storage at 4 degrees C and room temperature. Total ester contents increased 25-fold, with the greater increases coming at room temperature, whereas alpha-farnesene levels increased only 5-fold. For apples stored at room temperature, after 11 days, the amount of increase was inversely proportional to the size of the ester: levels of smallest esters (molecular weight 116) increased 12.5-fold, and the largest esters (molecular weight 228) increased approximately 1.3-fold.     

Effect of reddening-ripening on the antioxidant activity of polyphenol extracts from cv. 'Annurca' apple fruits

Apple is among the most consumed fruits worldwide, and several studies suggest that apple polyphenols could play a role in the prevention of degenerative diseases. 'Annurca' apple fruit undergoes, after harvest, a typical reddening treatment to turn the apples' skin red, and it is noted for its high firmness. This paper reports the effect of reddening-ripening treatment on polyphenol concentration and antioxidant activity of both peel and flesh extracts. The in vitro antioxidant properties have been compared with the protective effect against the cytotoxic effects of reactive oxygen species using Caco-2 cells as model system. Pretreatment of cells with different polyphenolic apple extracts provides a remarkable protection against oxidative damage. This effect seems to be associated with the antioxidant activity of 'Annurca' apple polyphenolic compounds. The flesh has antioxidant properties comparable to those possessed by the peel. Neither the reddening nor the fruit conservation causes changes in the antioxidant properties possessed by this apple variety. The data indicate that polyphenolic compounds in 'Annurca' apples are relatively stable in the peel and also in the flesh; therefore, the health benefits of polyphenols should be maintained during long-term storage. Finally, a diet rich in apple antioxidants could exert a beneficial effect in the prevention of intestinal pathologies related to the production of reactive oxygen species.     

Influence of the Fertilisation System on the Mechanical Damage of Apples

Fuji and Gala apples obtained with different fertilisation systems (soil surface application and fertigation) were submitted to drop tests to analyse the possible difference in susceptibility to damage. The tests were carried out by simulating two impacts of different severity that occur in a packing line. For the Fuji apples, a test was also carried out to assess the effect of a long storage period. For the test with the highest impact severity, the apple acceleration was recorded to describe the mechanical behaviour of the fruit and to correlate it with the damage. Logistic and multiple linear regressions were performed to assess the correlations between probability, extent and nature of damage, fertilisation systems and main characteristics of the fruits. The results show that the resistance to damage of Fuji and Gala apples is influenced by the fertilisation system both in probability and in characteristics of damage. Duration of storage can invert the susceptibility to damage, with the apples having a higher resistance to damage after a longer period of storage. Conventional fertilisation induced a high susceptibility to darkening and fracturing of the apples tissue. The parameters to describe the mechanical behaviour of apples were often correlated with the fertilisation system. However, their influence on extent and nature of damage was not significant or substantial while they can have a high effect on probability of damage. Fuji apples were found to be more susceptible to damage than Gala apples.     

Apples prevent mammary tumors in rats

Regular consumption of fruits and vegetables has been consistently shown to be associated with reduced risk of developing chronic diseases such as cancer and cardiovascular disease. Apples are commonly consumed and are the major contributors of phytochemicals in human diets. It was previously reported that apple extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. Phytochemicals, including phenolics and flavonoids, are suggested to be the bioactive compounds contributing to the health benefits of apples. Here it is shown that whole apple extracts prevent mammary cancer in a rat model in a dose-dependent manner at doses comparable to human consumption of one, three, and six apples a day. This study demonstrated that whole apple extracts effectively inhibited mammary cancer growth in the rat model; thus, consumption of apples may be an effective strategy for cancer protection.     

Characterization of Royal Gala apple aroma using electronic nose technology-potential maturity indicator

Changes in aroma of apple harvested at four different maturities were measured at harvest and after short-term storage using electronic aroma sensors ("electronic nose") and classical headspace/gas chromatography methods. Stored fruits were also evaluated by a trained sensory panel. Compared with headspace/gas chromatography, the electronic nose was found to be more sensitive ( approximately 40 times) in terms of sample size. The sampling procedure for the electronic nose was much less complex. Using discriminant function analysis, both methods classified the apples tested into groups according to harvest date. After storage, the groupings were more diffuse. Results from sensory testing showed partial separation along the first linear discriminant but did not classify the apple into distinct groups. Important differences between treatments were found for "overall flavor", "acid flavor" intensity, "crispness", "cider/fermented aroma", "vegetative aroma", and "canned pear aroma".     

基于特征光谱的苹果霉心病无损检测设备设计

针对现有农产品内部品质无损检测多采用宽波段光谱技术,集成应用光谱仪与计算机完成品质分析,存在成本高、能耗大、分析过程复杂以及光谱信息冗余等问题。该文结合苹果霉心病在果心发病的特征,采用透射光谱检测方式,设计实现了基于窄带LED光源与光敏二极管的苹果霉心病无损检测设备。通过霉心病发病特征的分析可得果径和特征光谱波段的透射强度是进行霉心病检测的关键影响因素,设计光谱特性试验,对多组宽波段光谱数据采用相关性分析法得到特征光谱波段为690～730 nm。设计果径与透射光谱信息采集的基础平台,该平台包括LED光源及其驱动模块、光电转换与检测模块以及基于丝杠滑台组件与限位传感器的果径在线测量模块;采用基础平台对样品进行数据获取,以果径与透射光谱强度值为输入,建立基于误差反向传播网络的霉心病判别模型。结果表明,采用该文所述测试试验样本进行验证,设备判别准确率达到95.83%。该研究结果表明,基于特征光谱采用 LED 光源的霉心病无损检测方法是可行的,可为其他果品内部病害的检测提供借鉴思路。     

Salicylic acid, ethephon, and methyl jasmonate enhance ester regeneration in 1-MCP-treated apple fruit after long-term cold storage

Volatile esters, primarily synthesized in peel tissues, are major aromatic components of apple fruits [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf.]. The use of cold storage combined with 1-methylcyclopropene (1-MCP) treatment prolongs the life of apples but represses the regeneration of esters during poststorage ripening. In this study, the regeneration of total esters was significantly increased in apple fruits treated with salicylic acid (SA) and Ethephon (ETH) that had been treated once or twice with 1-MCP. However, methyl jasmonate (MeJA) treatment resulted in regeneration of total esters after a single 1-MCP treatment. To determine the mechanism by which SA, ETH, and MeJA regulate ester regeneration, the apple alcohol acyltransferase gene (MdAAT2) was investigated at the mRNA, protein, and enzyme activity levels. Genes associated with ethylene perception were also investigated by RT-PCR. The results suggest that MdAAT2 controls ester regeneration and that MdETR1 plays a key role in ethylene perception and regulation of downstream MdAAT2 gene expression during poststorage. Ester compounds and concentrations differed in peels treated with different signal molecules, indicating that regulation of the pathway upstream of straight-chain ester biosynthesis depended on the regulation of lipoxygenase (LOX) and alcohol dehydrogenase (ADH) activity by SA, ETH, and MeJA during poststorage ripening.     

Regeneration of volatile compounds in Fuji apples following ultra low oxygen atmosphere storage and its effect on sensory acceptability

The aim of this work was to assess whether extra time spent under AIR conditions after storage in an ultra low oxygen (ULO) atmosphere could allow the regeneration of volatile compound emission without negatively affecting quality parameters and the consumer acceptability of Fuji apples. Fruits were stored for 19 and 30 weeks at 1 degrees C and 92% RH under ULO atmosphere conditions (1 kPa O 2:1 kPa CO 2) or under ULO conditions followed by different periods (2 and 4 weeks) in cold AIR atmosphere (ULO + 2w or ULO + 4w, respectively). Standard quality and emission of volatile compounds were analyzed after storage plus 1 and 7 days at 20 degrees C. Sensory attributes and acceptability were also determined after 7 days at 20 degrees C. The extra period of 30 weeks in an AIR atmosphere after ULO storage resulted in an increase in the concentration of the compounds that most contribute to the flavor of Fuji apples. These fruits were relatively well accepted by consumers despite a slight decline in firmness and acidity.     

基于改进YOLOv7的苹果生长状态及姿态识别

针对目前苹果在复杂环境下难以进行生长状态分类识别、姿态信息同步获取等问题,该研究提出了一种基于改进YOLOv7的苹果生长状态分类和果实姿态融合识别方法。首先改进多尺度特征融合网络,在骨干网络中增加160×160的特征尺度层,用于增强模型对微小局部特征的识别敏感度;其次引入注意力机制CBAM(convolutional block attention module),改善网络对输入图片的感兴趣目标区域的关注度;最后采用Soft-NMS算法,能够有效避免高密度重叠目标被一次抑制从而发生漏检现象。此外,结合UNet分割网络和最小外接圆及矩形特征获取未遮挡苹果姿态。试验结果表明,改进YOLOv7的识别精确率、召回率和平均识别精度分别为86.9%、80.5%和87.1%,相比原始YOLOv7模型分别提高了4.2、2.2和3.7个百分点,另外苹果姿态检测方法的准确率为94%。该文模型能够实现苹果生长状态分类及果实姿态识别,可为末端执行器提供了抓取方向,以期为苹果无损高效的采摘奠定基础。     

采后苹果电特性与生理特性的关系及其应用

为了了解果蔬的电学特性,并为果蔬品质自动化识别提供新方法,该文从生理特性角度分析了影响采后苹果电参数变化的原因。基于电参数的变化,将BP神经网络技术应用于苹果新鲜等级的识别。研究结果指出：采后红富士苹果相对介电常数的变化规律与乙烯释放量变化规律相似,电阻率与乙烯释放量变化规律相反,在乙烯释放峰出现时,相对介电常数达到最大值,电阻率达到最小值。根据采后苹果可溶性固形物含量和pH值的变化,将苹果分为3个新鲜等级,以相对介电常数和电阻率作为BP神经网络的输入特征参数,在2-20-3的网络结构下,苹果新鲜等级平均识别率达到79%。该研究为了解采后果品电特性变化的原因提供了信息,为基于电特性的新型果品内部品质检测技术的研究提供了基础。